initial basemap and operational layers are now optional.
Merge pull request #108 from DavidSpriggs/feature/allow-layers-to-be-optional

initial basemap and operational layers are now optional.
Update to version 3.10 of the JS API
Merge pull request #109 from DavidSpriggs/feature/update-to-3.10-api

Update to version 3.10 of the JS API
Adding upstream master and merging